The sheer cliffs of the 156-acre island drop vertically into a rich, deep-blue ocean that really does feel like the middle of nowhere.

Five participants in an educators' voyage to the Northwestern Hawaiian Islands left the comforts of the National Oceanic and Atmospheric Administration ship Hi'ialakai yesterday to spend the next week on this windswept rock.

Two archaeologists, two biologists and one teacher will sleep in pup tents, eat canned food heated on a camp stove and drink only the water they brought with them.

But they didn't get off at Nihoa to be comfortable. Everyone going ashore has a job to do.

» Scott Kekuewa Kikiloi, a University of Hawaii doctoral candidate in archaeology, and archaeologist Kehaulani Souza will map several ancient Hawaiian ceremonial sites.

» Beth Flint, a U.S. Fish & Wildlife Service biologist, will check the well-being of plants and birds on the island, something she has done seven times before.

» Pete Oboyski, an insect biologist with the University of California at Berkeley, will see if a ravenous grasshopper that ate most of the island's plants in 2002 and 2004 has returned.

» David Boynton, an environmental resource teacher at Kokee Discovery Center on Kauai and a photographer, will spend some time with each of the groups.

Oboyski will count the invasive gray bird grasshoppers (Schistocerca nitens), and he'll check on the 36 local native insects known to live on Nihoa.

Even if the grasshoppers -- which are related to the "locusts that wrought plagues of biblical proportions" -- are not there this year, they may have taken a toll, he said.

The grasshoppers are on all the main Hawaiian islands and have been seen on French Frigate Shoals and Mokumanamana (Necker) Island, but had never been seen on Nihoa in such warming numbers until 2002.

Other insect biologists reported that "most of the vegetation was completely chewed off," in 2002 and 2004, Oboyski said.

Oboyski will test five "flavors" of oils for their use as possible attractants for the grasshoppers. One will be orange oil, because a scientist who opened a fresh orange on Nihoa found that he was surrounded by grasshoppers within minutes, where before there had been none.

That anecdote about the sometimes serendipitous progress of scientific discovery set off a lively discussion among teachers on this voyage and the scientists who are sharing their research with them.

Teachers Barbara Mayer and Maggie Prevenas were so excited by the grasshopper saga that they crafted an online exercise for their students, asking them to guess what might have caused the population explosion.

They'll ask Oboyski to share what he observed on Nihoa with their students online, when the Nihoa five are picked up Saturday.

One possible silver lining in the dark cloud of grasshopper overpopulation may be that one of Nihoa's rare birds, the Nihoa Millerbird (Acrocephalus familiaris kingi), seems to have increased in numbers over the grasshopper years.

Flint, ever the cautious scientist, said it's not clear whether the larger Nihoa Millerbird numbers are because they've reproduced well on a diet of grasshoppers, or if it's simply easier to spot the secretive birds on bushes devoid of leaves.

Taking advantage of the unusually calm waters around Nihoa, the other nine teachers on this voyage snorkeled in its waters and circled the island in an inflatable boat.

They saw several of the sights that are just about guaranteed on a trip to Hawaii's most remote islands: monk seals, a shark and marine debris.

Two of those sights, unfortunately, were in the same eyeful. The small gray reef shark "was wearing a piece of debris rope around its middle like a halter," said Prevenas.